"I don't know if we're going to win this fight," Bill McKibben said on the Cahn Auditorium stage Tuesday night. "Dr. King always said the arc of the moral universe is long and bends towards justice. The arc of the physical universe appears short and bent towards heat."

"I do know that we are going to put up a fight."

Students for Ecological and Environmental Development (SEED) hosted environmental activist and author McKibben, who talked about all things climate change, both locally at Northwestern's campus and nationally in the White House.

McKibben has become well known in recent years for his work with 350.org in opposition to the proposed Keystone XL pipeline, which would bring oil from the Canadian tar sands to the United States.

Although the plan has been touted as a way for the United States to reduce its dependence on oil from the Middle East, environmentalists argue that it would further ingrain the country's dependence on fossil fuels. Such a move would be dramatically increase the amount of carbon released into the Earth's climate once the oil is refined and burned off as fuel.

"The deepest worry is that we are on a business-as-usual trajectory," McKibben said, noting that with the current levels of carbon being released into the atmosphere, the earth's temperatures could rise several degrees by the end of the century – more than the two degrees which is generally agreed upon as a safe threshold.

McKibben also spoke about his personal path from writing to environmental activism.

"If left to my own devices, I'd rather be at home typing," he said. "But at a certain point, some years ago, it began to dawn on me that another book would not have moved the needle."

McKibben, who wrote the first book for general audiences about climate change in 1989, said the data-driven argument over climate change was won over 20 years ago, but that the fight for action and policy still continues today.

"It turns out, that this argument, like most important arguments, turns on power, not, in the end, data," McKibben said. "There is someone on the other side, and that is the richest enterprise in the history of humanity," he said, referencing the fossil fuel industry.

McKibben showed the audience photos from 350's global campaigns, which have largely involved the communities that will most be impacted by rising sea levels, prolonged droughts and flooding caused by climate change. 350 has organized demonstrations on every continent, and McKibben showed the audience photos from areas including Pakistan, which has experienced some of the worst floods in its history due to more moisture in the air from warmer global temperatures.

"I'd always been told that environmentalism is something rich white people do," McKibben said. "Most of the people we are working with around the world are poor, black, brown, Asian or young – because that's what most of the world is composed of. They are just as concerned about the future as anyone else, maybe more so."

McKibben also endorsed Divest NU, the student campaign asking the University's board of trustees to divest funds from coal companies.

"If it's wrong to wreck the planet, then it's wrong to profit from that wreckage," McKibben said. "It's also stupid to invest in it, because you're not profiting from it anymore," he said, speaking of the long term damages that climate change will cause.

While 350 has organized protests and civil disobedience events – McKibben himself spent a few days in jail after protesting Keystone XL – SEED at Northwestern focuses more on educational events on campus, according to executive member Meredyth Gottschall.

"There isn't as much of an activist community at Northwestern, and we do have events that are catered towards people's tastes," Gottschall said, noting that last year's winter speaker was focused less on activism.

Bringing McKibben to campus returned the focus to the social justice activism which students sometimes miss out on while focusing on academics, she said.